Rotary pump and fan



Nov. 8, 1932. H. MAWSON 1,837,417

ROTARY PUMP AND mu Filed J ne 10. 1932 t I: '2 I N i I? I I;

Patented Nov. 8, 1932 UNITED STATES PATENT OFFICE HUBEBT IAWSON, OF LIVERPOOL, ENGLAND, ASSIGNOB N DRYSDALE AND COMPANY,

. LIMITED, OF GLASGOW, SCOTLAND ROTARY Pour AND ran Application filed June 10, 1932, Serial No. 616,651,.and in Great Britain August 81, 1931.

This invention relates to rotary pumps and fans of the axial flow or screw propeller type.

In pumps. and fans of this type it is desirable that each particle of fluid dealt with should enter the rotor with the same pressure and absolute velocity without slip; should have the same energy impressed upon it during its passage though the rotor; and should leave the rotor with constant pressure and absolute velocity. Otherwise, there result shock and cross-flow with consequential loss of ener VVIiih these desiderata in view the present invention consists of an axial-flow or screw 1| propeller pump or fan having a rotor constructed as a compounded screw, slipless, of radially constant pitch at entrance, and of radially varying pitch at exit, producing absolute exit velocities of the fluid equal in :0 ma 'tude at all radii, and whirl velocities WhlCh vary inversely as the radii.

The invention is illustrated in the accompanying drawing, in which Fi 1 is an axial section of a pump assembly. igs..2 and 3 developed sections of the rotor and guide vanes at radii 1' and B, respectively, (Fig. 1),

and Figs. 4 and 5 velocity diagrams for the rotor entrance and exit, respectively.

Referring to the drawing, 1 denotes the 80 blades of the ump rotor which rotates with in a casing 2 having a flared inlet or mouthpiece 3. The rotor is interposed between mlet guide vanes 4'integral with the mouthpiece 3 and exit guide, vanes 5 integral with the casing 2.

The rotor blades '1 radiate from a boss 6 secured on a driving shaft 7 journalled axially of the casing in a bearing 7 mounted in a stream-lined boss 8 unitary with the casing 2, the boss 6 bein interposed between the boss 8 and a streamined boss 9 integral with the mouth-piece 3.

The rotor is constituted as a compound screw, the pitch of the blades 1 being radially constant at the rotor entrance 1' and radially varying at the rotor exit 1, the radially varying pitch producing absolute exit velocities of the fluid equal in magnitudeat all Referring to Fig. 2, a1 and a2 denote the pitch angles on radius 1', at the entrance and exit, respectively, of the rotor blades, while 113 denotes the entrance angle for the exit guide vanes 5 at radius r.

Referring to Fig. 3, ,81 and B2 denote the pitch angles on radius R, at the entrance and exit, respectively, of the rotor blades, while B3 denotes the entrance angle for the exit guide vanes 5 at radius R.

In the velocity diagrams (Figs. 4 and 5) VpR denotes the peripheral speed at radius R and 'Vpr denotes the peripheral speed at radius r. Fa (Fig. 4) denotes the axial speed of the fluid at the rotor entrance. W0 and WR (Fig. 5) denote the whirl velocities at radii r and R, respectivel Va denotes the absolute fluid speed, which is radii.

The guide vanes 4, 5 may be dispensed wlth.

What is claimed is 1. In an axial flow pump or fan, a. rotor constituted as a com ound screw, slipless, of

radially constant pitch at entrance and of radially varyingpltch at exit, roducing absolute exit velocities of the magnitude at all radii and whirl velocities WhlCh vary inversely as the radii.

2. In an axial flow pump or fan, in combination with a casing having inlet and exit guide vanes, a rotor interposed between said guide vanes, said rotor being constituted as a compound screw of radially constantpitch at entrance and of radially va ing pitch at exit producing absolute exit v ocities of the fluid equal in magnitude at all radii and constant at all uid equal in whirl velocities whlch vary inversely as the radii.

tion.

HUBERT MAWSON.

radii, and whirl velocities which vary inc versly as' the radii.

I hereby sign myname to this specifica- 

